1. Field of the Invention
The present invention relates to a detergent dispensing apparatus, particularly to a detergent dispensing apparatus that releases a well-defined quantity.
2. Description of Related Art
Toilets with a toilet bowl and a cistern are regularly used in daily life, yet are not easily kept clean. To keep a toilet clean, adding a small amount of a detergent to water is helpful. The detergent is directly applied during manual cleaning or added to water in the water reservoir. Then each flush brings some detergent into the toilet bowl, giving a cleaning effect that is attained without requiring time and manual work.
There are two ways to add detergent to water in a cistern. One is to put cleaning material with dye adsorbed in a holder of inert material into the cistern, forming a solid cleaner block. The cleaning material with dye will then be slowly dissolved in water. A weakening color of the water will indicate that the cleaning material is running out and the cleaner block needs to be replaced. The other way to add detergent to water in a cistern is to place a container holding cleaning liquid inside the cistern. When the water level in the cistern changes, cleaning liquid from the container is dispensed by a dispensing system. However, the two systems just described have disadvantages. The cleaner block gives off cleaning material at a certain rate, leading to a concentration of cleaning material in water that depends on the time elapsed since the toilet was flushed last time. So the cleaning effect of the cleaner block varies with flushing intervals. Furthermore, the right moment to replace the cleaner block is not clearly found. Finally, the cleaner block disintegrates and falls to the bottom of the cistern, dissolving into muddy material which is hard to remove. The container with cleaning liquid does not have the shortcomings of the cleaner block just mentioned, but needs an adequate design of the dispensing system to ensure proper outflowing of cleaning liquid.
Previous patents have disclosed two types of dispensing systems for the container with cleaning liquid which are operated by changing of the water level in the cistern. To connect the container and a floating body, these two types use a moving or control bar and a flexible tube, respectively.
The moving or control bar of the first type has an elongated opening or groove or lateral channels to conduct cleaning liquid. When the water level in the cistern rises, taking along the floating body, the moving bar or control bar is thereby pushed into the container, and cleaning liquid enters the elongated opening or groove or lateral channels. When the toilet is flushed, the water level in the cistern decreases, the floating body is lowered and pulls down the moving or control bar, releasing cleaning liquid into the cistern.
The details of related patents are as follows:
Taiwan patent no. 237056, filed by Guo Zhongyan, uses a groove on a valve bar that is moved between inside and outside the container through a cap by rising and lowering of the water level. Thus a fixed quantity of cleaning liquid is released. Taiwan patent no. 244574, filed by Huang Facai, has a control bar moved with the floating body by a certain amplitude, ensuring that a fixed quantity of cleaning liquid is released. Taiwan patent no. 275894, filed by Zhan Zitong, has a floating body which by buoyancy drives a feeding element upward into the container, where an elongated opening in the feeding element takes in cleaning liquid. When the toilet is flushed, the feeding element goes down, and cleaning liquid is released from the elongated opening. Taiwan patent no. 251605, filed by Li Kunchang, uses a floating body, having a cross head bolt and a ball, which moves upward and downward with the water level in the cistern, so that cleaning liquid flows through lateral channels in the cross head bolt according to the upward and downward movement thereof. Taiwan patent no. 351365, filed by Huang Facai, has a bar, moving upward and downward with the water level in the cistern, with a plug regulating the released quantity of cleaning liquid, for automatic flowing and blocking at appropriate times.
The moving or control bars in the patents explained above glide through the cap of the container between the inside and the outside thereof. Too tight a contact with the cap causes too much friction, too loose a contact causes dripping out or leaking of cleaning liquid into the cistern, so that after a long flushing interval too high a concentration of cleaning liquid has entered the cistern. This is both uneconomical and bad for the environment.
In order to solve the problem of dripping or leaking cleaning liquid, upper and lower plugging rings are inserted as seals, or a sealing ring is used at the container outlet. However, due to gliding structural parts, effective sealing is not attained, and stable dispensing of cleaning liquid is not realized.
The details of related patents are as follows:
Taiwan patents no. 289366 and 340546, filed by Liao Lirong, have a container, a connecting piece, a flexible tube and a floating body. The floating body is raised or lowered according to the water level in the cistern. With the floating body experiencing a buoyant force along with the water level rising, the flexible tube is taken along, driving a shutter element that causes liquid inside the container to flow out through a hole in the connecting piece into the cistern. The floating body and the flexible tube have a watertight connection. In another file, a protective cap is added which, by a determined distance from the container, controls the quantity of outflowing liquid.
The patents just described teach, with the flexible tube forming a connection between the container and the floating body how to avoid leaking of cleaning liquid by a principle of pressure balance. However, when the cistern is full of water, a connection is established to liquid in the conduit between the container entrance and the flexible tube, and the pressure balance is upset. Since cleaning liquid in high concentration often has a higher density than water, cleaning liquid will slowly seep into the conduit between the container entrance and the flexible tube. Furthermore, when lifted by the water level rising, the floating body possibly is tilted, resulting in a not well-defined quantity of cleaning liquid to be released and resulting in the need to install another protective cap.